Quick connectors of this type are known in the art from DE-C-1902986, U.S. Pat. No. 2,913,263 and U.S. Pat. No. 3,336,944. These quick connectors primarily serve to create a rapid connection between a sleeve (female part) and a plug (male part) by hand without the assistance of a tool which can be disconnected rapidly in a similar manner. The sleeve is normally stationary e.g. on a pressurized air supply, and the plug is normally secured to a pressurized air tool or mounted to an associated hose. Quick connectors are mass production articles and substantially replace the connection hose nozzle, hose and hose band clamp. Quick connectors are primarily used for pneumatic applications in particular in pressurized air technology and in hydraulic applications e.g. in chemical technology. Two cylindrical locking pins made from steel are used as locking elements for securing the plug to the sleeve. They are guided in slots introduced in the sleeve body at approximately 45.degree. with respect to the middle axis. The locking pins project along their entire length beyond the outer diameter of the sleeve body and can be displaced diagonally with respect to the middle axis by a bushing, axially displaceable on the sleeve body. The pressurized spring surrounding the sleeve body pushes, via a pressure ring, the locking pins in such a manner that they move towards each other to a separation corresponding approximately to the diameter of the plug groove. This locking mechanism has the advantage of allowing simple one-hand operation. The plug can be inserted into the sleeve and locked therewith using one hand without having to pull back the bushing with the second hand. For disengagement, the bushing is moved by hand in opposition to the spring force. The locking pins are thereby displaced to their largest possible separation which exceeds the diameter of the plug enlargement. The plug is then released. Locking using locking pins is a particularly economical solution compared to other conventional locking mechanisms e.g. the ball lock e.g. of DE-OS-2558650. The ball lock necessitates displacing an additional spacer bushing below the ball for removing the plug in order to effect the desired single hand operation. In U.S. Pat. No. 4,198,080, the bushing is eliminated, but with the associated disadvantage that two hands must be used for locking.
DE-OS-1250698 discloses a quick connector having a ball lock, whereby different types of plugs fit into the sleeve. This configuration has disadvantages similar to those of DE-OS-2558650 of requiring an additional spacer bushing below the ball. Introduction of the radial ball bore in sleeve bodies made from metal is expensive and requires an additional processing step. If the sleeve body were made from plastic, high loading of the balls would press the balls into the ball bore. All of the above mentioned quick connectors with the exception of OS-1250698 have the disadvantage that only one type of plug fits into a sleeve body, since the sleeve body is adapted to the respective shape of the plug. Given a plurality of plug contours, an equally large number of sleeve bodies are thereby required. Conventional quick connectors having locking pins have the particular disadvantage of requiring a peripheral groove for the sealing ring on the inner bore of the sleeve body. This groove, due to the undercut, impairs removal after molding of a plastic sleeve body made using an injection molding tool.
Quick connectors with locking pins having some of the features claimed have also been used throughout the entire European market, e.g. those provided by the company FESTO of Germany. These quick connectors have hollow cylindrical sleeve bodies usually made from metal, rarely from plastic, and having diagonal slots for the locking pins. The diagonal slots in the metallic sleeve body are milled into the hollow cylinder using a disc milling cutter. A slot of this type penetrates through the sleeve body both in a direction longitudinal with respect to the middle axis of the locking pins as well as in a direction of an approximately 45.degree. diagonal axis. The conventional plastic sleeve bodies also have two diagonal slots penetrating through the sleeve body which are machined, as is the metallic sleeve body, using a disc milling cutter. The associated penetration through the sleeve body of the diagonal slots up to the peripheral jacket is disadvantageous, since this leads to substantial weakening of this member. This is substantially more disadvantageous with plastic than with metal. These quick connectors also have the disadvantage that the sleeve body must be adapted in each case to the corresponding type of plug with respect to the associated length of the plug contour as well as with respect to its receiving diameter. A further disadvantage is that the groove for the sealing ring must be machined in the inner bore of the sleeve body. When metal is used, this recess is expensive to produce. When plastic is used, the piece cannot be removed after molding, as was mentioned above. An additional disadvantage of the conventional quick connectors having sleeve bodies made from plastic is that the locking pins, in particular for high pressure applications and under pulsing loads, are pressed into the diagonal slots of the sleeve body and cause permanent deformations leading to malfunctioning.
A quick connector having the features of the invention is also known in the art through DE-OS-2705319 wherein one sleeve (in this case a plug connection valve) is proposed for three differing plug contours (in this case insertion members). This arrangement has the advantage of the adaptability of the sleeve body to three different plugs. It has, however, the disadvantage of a complicated construction having a large number of individual parts and therefore a large size. A further disadvantage is that it is only possible for differing plug shapes to be accommodated in one type of sleeve to a highly limited degree. For example, plugs having a different diameter in the forward cylindrical portion for sealing in the sleeve body no longer fit into a common sleeve body (in this case referred to as the valve casing). A further disadvantage is that the undercut for the sealing ring must be machined into a sleeve body made from plastic and the locking pins are pressed into the diagonal slots under high pressure loads.
Past developments in various different countries have led to different conventional plug contours. The present invention concerns five different plug shapes. A plug shape designated here as type I has been particularly widespread in Germany, Austria and Eastern Europe and is clearly illustrated in FIG. 2 of EP-B-0536434. A plug contour referred to herein as type II, has become very widely used in Scandinavia. A type III plug contour has been primarily used for the coupling of fluid conduits. The type IV plug profile is conventional according to ISO 6150 and US-Military Standard C-4109D as well as AFNOR E 49-053 and is widely used in the USA and in France. A plug contour of type V is widely used in Switzerland and is clearly described in EP-B-0013393. These differing developments have the following disadvantages: a manufacturer of quick connectors of the above 5 types must normally modify nearly all individual components for each plug shape. In particular, the sleeve body must be adapted to the respective plug contour. Most plug contours, as is the case in the current invention, require 5 differing sleeve bodies having diameters and longitudinal dimensions adapted to the respective plug shapes. Sleeve bodies made from metal having e.g. a peripheral groove for the seal recess at the inner bore require additional milling of the diagonal slot and substantial lathe machining. The production costs of a metallic sleeve body are approximately 50% of the production costs of the entire quick connector. For this reason, injection molded plastic sleeve bodies are particularly advantageous. However, this requires the manufacturer of quick connectors of the kind with which the present invention is concerned, to use five differing injection molding tools.
In contrast thereto it is the purpose of the present invention to create a quick connector having the above advantageous features and with easy handling which facilitates only one single sleeve body for all five differing plugs without having associated disadvantages such as a narrowing of the flow cross section or increased spatial dimensioning. An additional purpose of the invention is to replace the conventional sleeve body made from metal and having milled diagonal slots with more economical sleeve bodies made from plastic without the locking pins being pressed into the plastic under high load. It is an additional purpose of the invention to eliminate the machined peripheral groove for the seal of the conventional quick connector at the inner bore of the sleeve body without having to change the seal ring bearing as e.g. done with the ball lock. An additional purpose of the invention is to integrate the holding function of the spanning ring of the conventional solution, which secures the bushing in an axial fashion, directly into the sleeve body.